The use of awnings as store front signs, and also as decoration on store windows, and their use on private dwellings, and on commercial and industrial buildings and public buildings both for decoration and for the exclusion of, and shading from, the sun, is widespread.
In the design of such awning structures numerous different considerations must be accounted for. Thus the awning must have a pleasing aesthetic appearance, and be capable of resisting severe wind and weather conditions in many cases, and must have a lengthy life span.
On the other hand it must be made in a simple manner using a minimum of different components, such that it can readily be assembled with the simplest of hand tools, in order to keep its cost down to a minimum.
In practice, the great majority of such awnings are made up on the basis of some form of framework usually of extruded aluminum, on which is supported some form of fabric covering such as canvas, or vinyl, or nylon coated fabric.
A wide variety of such materials are available, and customers may select one or the other for a variety of reasons, and it is desirable to provide a system accommodating as far as possible relatively wide variations in customer tastes, and budgets.
One usual factor in the design of such awnings which is desired by the great majority of customers, is the fact that the awning should have a convexly curved or contoured exterior shape. Usually, the awning structure will have a flat surface which can be placed substantially vertical on a vertical face of the building, usually just over a window or doorway. Usually, such awnings as are used on store fronts will incorporate some form of electrical receptacles, and lighting tubes, so that illumination can be thrown downwardly from the awning onto the front of the building.
Usually, such awnings will incorporate a bottom frame, with or without a bottom wall, which is generally substantially horizontal although it can be angled at a angle if desired. The bottom frame, or wall, usually (in an illuminated awning) incorporates some form of lens structure for allowing passage of light from the lighting tubes. In the majority of cases the lens structure is simply a grid of for example translucent plastic material, defining a large number of holes, somewhat in the manner of an egg crate divider. However a great many other forms of lens structures in various materials are available.
In other forms of signs, the lens structure may be replaced with panels, which may themselves support lighting fixtures, so that the lighting fixtures can be oriented at desirable angles for various lighting effects.
Usually, the portion of the awning which extends from the top of the vertical portion, to the outwardly extending edge of the horizontal portion, is comprised of a curved shape, in some cases continuously curved, and in other cases being partially curved and partially straight. It may be rounded at each end, or may have planar end panels.
It is usually a requirement that the fabric material of the awning shall be stretched tightly over this curved frame, and shall also be fitted tightly around the ends of the frame, so that at each end, the awning defines substantially vertical end panels which have a vertical side edge, a horizontal side edge, defining a generally L-shape, and a curved contour extending between the free ends of the L-shape.
Thus the piece of fabric at each end of the awning may be cut more or less as it were in the shape of a quarter-round in section, or in a series of arcuate sections or segments, tailored to the desired shape.
While the design of the frame itself to support such a fabric awning does not appear to present serious problems, in practice, the tailoring and fitting of the fabric so that it fits tightly over the frame does present problems. In the past, in the great majority of cases, the fabric has been required to be cut in at least three portions, for example a rectangular portion covering the forwardly extending curved surface of the awning, and two quarter-round portions, filling in each end. The three portions will then be sewn together, and snugly and tightly drawn over the frame.
The skills and techniques required for such cutting and sewing somewhat resemble the skills and techniques required for the accurate fitting of furniture coverings and upholstery materials. It is well known that these skills require many years of practice, and are not easily attained by everyone.
In addition, the requirement for sewing of these materials has meant that the factories where the awnings and signs are being fabricated must be equipped with sewing facilities. These sewing facilities must be capable of sewing heavy duty fabrics, and appropriately trained and skilled personnel must be kept on staff. The fabric used for such signs and awnings is relatively expensive. In addition, it is usually the practice to print some form of message on the front portion of the sign, for example by silk screening. This involves further skills, and increases the cost of the sign.
If there are any errors made in the cutting or sewing of the sign, it may be that all of the fabric must be discarded, and work started again. This means not merely that the cost of the material is a waste but also that the work involved in the silk screening of the sign and the like is also wasted.
For all of these reasons therefore the use of the tailoring and fitting and sewing techniques required in the manufacture of conventional awnings and signs has been regarded with considerable disfavour by the industry.
In the past, various attempts have been made to overcome this. For example, in U.S. Pat. No. 4,690,192 inventor Johann Stilling, for Replaceable Awning, issued Sep. 1, 1987, there was disclosed a form of framework for an awning, wherein the fabric portions of the awning were held in place by a continuous extruded thermoplastic plug member or wedge, by means of which the edge of the fabric was force fitted into a groove in the extrusion and securely held in position. This avoided the requirement for sewing.
Another variation on this technique, was to secure a receiving body in the extrusion and then to take the edge of the fabric and stretch it tightly over the plastic extrusion, and then simply staple through the fabric into the receiving body in plastic extrusion.
This system represented something of an improvement over the conventional sewing and stitching techniques employed in the past. However, certain disadvantages were inherent in the frame design in the aforesaid patent. As mentioned above it is generally desirable that the front of the awning shall be contoured or curved so as to provide as it were a "bonnet" or "umbrella" effect. In order to do this, it is necessary to fabricate a frame for the awning in which a number of the frame members are curved around a predetermined radius of curvature, so as to provide a uniform contour along the length of the sign or awning.
The aforesaid patent discloses a somewhat complex cross-section for its frame extrusion, and this in turn presented somewhat of a challenge from the view point of achieving a satisfactory smooth curve when the extrusion was bent. In practice, specialized bending machinery had to be developed in order to produce satisfactory repeatable curves in this extrusion.